Screw jack



E; J. VAN FLEET.

SCREW JACK.

APPLICATION FILED SEPT. 30, 1921.

Patented Nov. 2 1, 1922.

2 SHEETS-SHEET 1.

E. J. VAN FLEET.

SCREW JACK. APPLICATION FILED SEPT. 30. F921.

Patented Nov. 21; 1922.

2 SHEETS-SHEET 2.

liifii linmil iz II-IIIIIIIIIIIIHIH 1 Fatented Nov. 21, 1922.

warren s lk i x M we w my a ELON J. VAN FLEET, OF JOLIET, ILLINOIS, ASSIGNOR TO "WILLIAM E. PRATT, OF

CHICAGO, ILLINOIS.

SCREW JACK.

Application filed. September 30, 1921. SerialNo. 504,431.

To aZZ whom it may concern:

Be it known that ELcrI J. VAN F LEET, a citizen of the United States of America, residing at Joliet, in the county of Will and State of Illinois, has invented certain new and useful Improvements'in Screw Jacks, of which the following is a specification.

This invention relates to jacks and especially to the type of vjack used around automobiles and the like.

More particularly the invention relates to a screw jack for automobiles.

It is a well known fact that in jacks this description they are constructed with a view to enabling the jack to be sold at a very low figure. Consequently there is as little machining employed in connection with such jacks as is possible. For instance it is common to have a tubular base with a 20 stub shaft cast on one side thereof on which fits a bevel gear which meshes with a bevel gear threaded on the jack screw. In the ordinary construction the bevel gear first mentioned is cast and neither the hole in the gear nor the stub shaft is subjected to any refinement of finish. Outside of the bevel gear on the same stub shaft is located the operating lever which is held in position by an ordinary cotter pin. Such a construction as this necessitates great clearances between the parts to make up for any qualities due to the rough castings and in consequence of the looseness of the first gear on the shaft and the looseness of the lever. On the same shaft there is a great deal of play which permits the first gear to edge away from the second gear.

One important object of the invention is to provide an improved construction wherein the looseness due to the rough casting will be in a great measure obviated.

Also in jacks of this description the pawl on the operating lever'is usually held in position by a cotter pin. In consequence 45 there is also at this point too great a looseness of the parts.

A second important object of the invention is to provide improved means for connecting the pawl and lever so that the cotter pin commonly used may be dispensed with and also so that these parts may have the looseness obviatedfto a great extent.

Another feature of jacks of this class has heretofore been that in order to prevent rotation of the screw it has been necessary to machine the screw to provide a spline way and to fix within the standard or base a key running in this spline way.

A third important object of the invention is to provide an improved form of jack wherein the screw and standard or base will be provided with integral cooperation means to prevent rotation of one of these parts relative to the other.

With the above andother objects in view, the invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings, and specifically claimed.

In the accompanying drawings, like characters of reference indicate like parts in the several views, and:-

Figure 1 is a. side elevation of the improved jack constructed in accordance with this invention.

Figure 2 is a partial section on the line 2--2 of Figure '1 showing the hub and stub shaft arrangement in detail.

Figure 3 is a detail section on the line of Figure 1.

Figure 4 is a perspective view of the improved form of pawl.

Figure 5 is a front view of the working parts of the modified form of the invention.

Figure 6 is a side view thereof.

Figure 7 is a detail section on the line 77 of Figure 6.

Figure 8 is a detail perspective of the modified pawl.

Figure 9 is a view of the lower part of the jack screw.

In carrying out the invention there is provided a base or standard having a foot 10 and a hollow column 11 having a channel 12 cast in each side. Through this column 11 extends a jack screw 18 having its lower end 14 forged to provide a pair of fins or keys 15 which fit slidably in the channels or grooves 12. On the upper end of this screw, which projects above the column 11, is fixed a head 16 and resting on top of the column is a miter or bevel gear 17 which isthreaded interiorally to fit the screw 13 and thus constituting a geared nut. Oast integrally with the column 11 and projecting from one side thereof is a stub shaft 18 whereon is mounted a. second bevel gear 19 meshing with the first bevel gear and having an elongated hub 20. On this hub 1:30

"alug 28 formed on the free end of a-pawl 29 having a short stub shaft 30 projecting from its opposite end and passing through the opening in the lever; on the end of this stub shaft are formed. diametrically disposed lugs 31 which are a proper size and pass through the slots 25 with the pawl 1D.

' one position but which, when the pawl as- -18 by a washer 32 and cotter sumes any other position, prevenhdisengagement of the pawl from the lever end 24. It will be observed from Figured that the pawl is there shown in position to lower the head 16 but that this pawl maybe thrown over on the opposite side of the'lever portion 24 into raised position for the head 16.

From the construction shown in Figure 2 it will be observed that the elongated hub 20 and the bearing 21 are held on the shaft It will also be observed that this elongated hub tends to prevent any cocking of the gear 19 on the shaft 18 such as would take place where the hub shortens and the bearing 21. engages directly on the shaft 18.

It will be observed from Figure 8 that the channels and lugs 15 eliminate the necessity of machining a spline way and the employment of a separate key. It will also be observed that the construction of the pawl shown in Figure 4 is such that no cotter is needed to hold the pawl in position and that a sufliciently accurate fitting of the pawl in position may be obtained by the simple expedient of spot finishing of part 26. a

It will. be noted that the .modified forms shown in lligures to 8 incl usive differ somewhat from the 'l oregoing description.

For instance the angularly disposed portion 27 of theoperating lever has an offset portion-3 L which, when the device is assembled, overhangs the teeth 27. Also the pawl used in this case is provided with a U-shaped body 35 the lugs of which straddle the portion 34 so that they may be held pivot-ally on this portion by means of a hollow rivet 36,

this taking the place of the key hole slot in the first form. a This pawl is providedwith a head terminating the lugs 37 engageaiblelbetween adjacent teeth 27 and the pawl also has a finger piece 38 projecting from one side. Furthermore with this construction the stub shaft 18 is simply riveted over a washer 38 as shown at 39.

It will be obvious that in place of the hollow rivet 36 the key hole slot arrangement may be employed in connection with the offset 34:.

From the foregoingvit will be seen that a highly efiicient jack may be constructed in this manner from east or drop forged parts without the necessity of refinements in machining and that consequently the construction lends itself to a great economy in manufacture.

There has thus been provided a simple and efiicient device of the kind described and for the purpose specified.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material principles thereof. It is not therefore desired to confine the invention to the exact form herein shown and described, but it is wished to include all such as properly come within the scope claimed.

Having thus described the invention, what is claimed as new, is 2-- 1. As a new article of manufacture, a ack screw tH'OVltiGtl with means for preventing ,rotatioii thereof formed integrally with the wheel, an operating lever pivoted at the axis of said ratchet wheel and free to oscillate with respect to the ratchet wheel, said lever having one arm provided to the handle portion and its opposite arm providedwith a 7 cyl ind rical openiiiig-having d i annetricnlly div posed slots extending through said arm from said opening, and a pawl having a'body portion provided with a stub shaft extending from one sidethereof through the opening in the operating lever, said stub shaft having diametrically disposed lugs adapted to pass through the slotted portions in the lever with the lever and pawl in a predetermined position, said lugs being arranged toprevent removal of the pawl from the lever in all other positions of the pawl and lever.

In testimony whereof I afiix my signature.

ELON J. VAN FLEET. 

